TuHURA Biosciences Receives FDA "Study May Proceed" Notice and IND Clearance for the Evaluation of its TBS-2025 VISTA-Inhibiting Antibody in Molecularly Defined Subsets of AML and Other Blood-Related Cancers

TAMPA, Fla., Sept. 14, 2026 /PRNewswire/ -- TuHURA Biosciences, Inc. (NASDAQ:HURA) ("TuHURA" or the "Company"), a Phase 3 immuno-oncology company developing novel therapeutics to overcome resistance to cancer immunotherapy, today announced that the U.S. Food and Drug Administration (FDA) has given clearance to TuHURA's Investigational New Drug (IND) application for its TBS-2025 VISTA-inhibiting antibody for molecularly defined subsets of Acute Myeloid Leukemia (AML) and other blood-related cancers.

The "Study May Proceed" notice from the FDA allows the Company to examine TBS-2025 in a Phase 1b study evaluating the safety and potential efficacy of monotherapy at different doses in patients with relapsed/refractory (r/r) mutNPM1 AML who have failed to respond to or relapsed after menin inhibitor therapy. Following review of the safety data with the FDA, the study is expected to progress to the dose-optimization stage of the trial to determine a safe and biologically effective dose. Patients with r/r mutNPM1 AML who fail menin inhibitor therapy have no approved or effective treatments and represent an unmet medical need. If TBS-2025 results in encouraging response rates during the dose optimization stage of the study, the Company will explore with the FDA the potential expansion of the trial in consideration for the opportunity for accelerated approval.

"As the only known company to advance a VISTA-inhibiting mAb through the FDA's IND process into a Phase 1b study in mutNPM1 AML, this is a major milestone for the Company and a testament to our commitment to advancing novel therapies to address the unmet needs of patients with AML," said Dr. James Bianco, President and Chief Executive Officer of TuHURA Biosciences. "Research has shown that patients whose leukemic cells express VISTA have a poor response to therapy and significantly shorter survival. Studies have demonstrated that TBS-2025's ability to block VISTA on leukemic cells has resulted in dramatic improvement in survival in studies of murine models of human AML, and we hope to translate this promising underlying science into a potentially safe and effective new treatment for patients with AML. We are excited for this next phase of our growth and by what it could mean for patients with AML."

About TBS-2025
TBS-2025 is a unique VISTA-inhibiting monoclonal antibody. VISTA is a novel checkpoint expressed on quiescent (resting) T cells and highly expressed on myeloid cells, notably myeloid-derived suppressor cells (MDSCs). Scientific evidence demonstrates that mutNPM1 drives the expression of VISTA on leukemic blasts, which is reported to be the primary mechanism by which AML escapes recognition by the patient's immune system, resulting in low response rates of short duration following current therapies, including recently approved menin inhibitors. When VSIR, the gene that encodes for VISTA, is edited not to produce VISTA in murine models of mutNPM1 AML, an immune response is observed and survival is enhanced. Similarly, in a murine model of AML, TBS-2025 resulted in an increase in survival comparable to the intensive chemotherapy regimen that is currently used in front line treatment of patients with AML. When combined with intensive chemotherapy, survival was markedly improved. Collectively, these translational data underscore the potential for TBS-2025 in the treatment of patients with AML.

About TuHURA Biosciences, Inc.
TuHURA Biosciences, Inc. (Nasdaq: HURA) is a Phase 3 immuno-oncology company developing novel technologies to overcome primary and acquired resistance to cancer immunotherapy, two of the most common reasons cancer immunotherapies fail to work or stop working in the majority of patients with cancer.

TuHURA's lead innate immune agonist, IFx-2.0, is designed to overcome primary resistance to checkpoint inhibitors. TuHURA has initiated a single randomized placebo-controlled Phase 3 registration trial of IFx-2.0 administered as an adjunctive therapy to Keytruda^® (pembrolizumab) compared to Keytruda^® plus placebo in first-line treatment for advanced or metastatic Merkel Cell Carcinoma.

In addition to its innate immune agonist product candidates, TuHURA is developing TBS-2025, a VISTA-inhibiting mAb moving into Phase 1b/2 in mutNPM1 r/r AML, a molecularly defined subgroup of patients with AML. In addition, TuHURA is leveraging its Delta Opioid Receptor technology to develop first-in-class, bi-specific, bi-functional antibody drug conjugates (ADCs) targeting Myeloid-Derived Suppressor Cells to inhibit their immune-suppressing effects on the tumor microenvironment to prevent T cell exhaustion and acquired resistance to checkpoint inhibitors and cellular therapies.

For more information, please visit www.tuhurabio.com and connect with TuHURA on Facebook, X, and LinkedIn.

Cautionary Statement Regarding Forward-Looking Statements
This press release contains certain "forward-looking statements" within the meaning of, and subject to the safe harbor created by, Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995. These forward-looking statements are based only on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, projections, anticipated events and other future conditions. In some cases, you can identify these statements by forward-looking words such as "believe," "may," "will," "estimate," "continue," "anticipate," "intend," "could," "should," "would," "project," "plan," "expect," "goal," "seek," "future," "likely," or the negative or plural of these words or similar expressions. Our statements in this press release regarding our planned Phase1b study of TBS-2025 is an example of such forward-looking statements. You are cautioned that such statements are not guarantees of future performance and that actual results or developments may differ materially from those set forth in these forward-looking statements. Factors that could cause actual results to differ materially from these forward-looking statements include, among others, the risks associated conducting the planned Phase 1 study of TBS-2025 and the general risks associated with continuing the development of TBS-2025; risks related to patient enrollment, trial design, data outcomes and regulatory interactions; uncertainty regarding the timing and likelihood of regulatory approvals; and the other risks described from time to time in detail in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, as filed on March 31, 2026, and TuHURA's other reports and filings with the SEC from time to time, which are available on TuHURA's website and at www.sec.gov.

The forward-looking statements and other information contained in this press release are made as of the date hereof, and TuHURA does not undertake any obligation to update publicly or revise any forward-looking statements or information, whether as a result of new information, future events or otherwise, unless so required by applicable securities laws.

Investor Contact:
Monique Kosse
Gilmartin Group
[email protected]

SOURCE TuHURA Biosciences, Inc.